Investigators in this project will continue to benefit from a state of the art facility, with advanced nstrumentation and highly trained technicians at their disposal. The personnel have unique experience in sorting extremely rare cells to high purity and in obtaining nine color data with small sample sizes. They routinely handle human specimens with biohazard precautions, and can work with spores, live bacteria and bacterial products. There is no equivalent expertise in the State of Oklahoma. Costs are contained in part by OMRF institutional support. Training is another important activity of this core facility. While investigators can simply hand samples to the technicians and receive formatted data, they are encouraged to learn at least how to analyze their own results. Most students and postdoctoral fellows prefer this, and a few have even earned how to sort on the FACSAria with close supervision. Advice on related procedures, such as reagent selection and magnetic bead enrichments is also readily available. Many appropriately labeled antibodies are available to facilitate pilot experiments and encourage innovation.